Portable communication devices inform the wearer of an incoming call by ring tones or body sensory vibrations generated by the rotation of eccentric weights of a built-in vibration motor. These modes are switched as necessary. Some game machines let the operator sense vibrations generated by the vibration motor in the machine in the course of games for more fun.
The above vibration motor is secured to a circuit board in the device/machine and generates and transmits vibrations to the device/machine housing, whereby the wearer/operator senses the vibrations. Such an example is described in Japanese Patent Application Laid-open No. H11-234943, wherein a vibration motor is mounted on a circuit board in such a manner that a cylindrical motor body is retained by a metal holder frame from below, a half-moon-shaped eccentric weight is fixed to one end of a motor shaft, creamed solder applied to the holder bottom is melted in a heating furnace to secure the entire structure to the circuit board.
The vibration motor is mounted in an automated process in which the motor body having an eccentric weight is retained in a holder frame to make a vibration motor unit, which is placed on a circuit board at a predetermined position, conveyer-transferred, heated in a heating furnace to melt the solder on the circuit board, and cooled to solidify the melted solder to secure the holder frame to the circuit board.
The vibration motor unit retained in the holder frame is simply placed on a circuit board while conveyer-transferred and, therefore, fairly unstable. Slight external vibration or extraordinary movement of the conveyer may cause the unit to fall over. If one of a plurality of vibration motor units placed on circuit boards transferred in a line falls over, the entire conveyer has to be once stopped to raise the vibration motor unit fell before the mounting process resumes. The transfer should be monitored and the work performance is significantly low.